The present invention relates to rolling bearing cages and more specifically to cages made of an elastic material having a structure providing for a predetermined amount of elastic resilience to prevent harmful stress of the cage material as the result of dimensional changes caused by fabrication tolerances or heat expansion.
Rolling bearing cages having elastic resilience are not new per se. In accordance with a prior cage, one of the two abutting end faces of the cage has a laterally closed recess providing a certain amount of elasticity in a peripheral direction. This end face preferably has a shoulder in the vicinity of the laterally closed recess which projects in a peripheral direction and engages the opposing end face under a certain amount of pre-tension. By this arrangement, the cage has the capability of springing radially outward in the direction of the bore of the outside ring of the bearing or the bore of the housing so that the play of the roller bearing cage and/or the rolling elements in the cage pockets is eliminated. Consequently the formation of a harmful ridge in bearing races is avoided which can occur when the bearing is temporarily in a stationary position. Formation of these ridges is commonly called "false brinelling" which may be defined as localized fretting, arising when rolling elements of a bearing oscillate with small amplitude while pressed against a race surface, as in a stationary bearing subjected to vibrations.
It has been found, however, that there are certain drawbacks and disadvantages in a cage of this type. For example, the elastic resilience provided by the closed recess is comparatively small especially in narrow roller bearing cages with the attendant result that a harmful excess stress of the cage material can be produced by dimensional changes of the rolling bearing due to fabrication tolerances or heat expansion produced by elevated temperatures under operating conditions.
With the foregoing in mind, it is an object of the present invention to provide an improved rolling bearing cage of the above type which prevents ridge formation or "false brinelling" and wherein the elastic end faces have a relatively large amount of spring in a peripheral direction. It is also an object to provide a roller bearing cage of this type which can be produced economically and efficiently.